In recent years there have been marketed blade units including a plurality of blades, in particular having two, and more recently three, blades arranged with their cutting edges extending parallel to each other for contacting the skin between guard and cap surfaces also provided by the blade unit. The performances of these blade units is enhanced by certain guard and cap structures, such as an elastomeric strip on the guard with a series of upstanding fins and a shaving aid strip included in the cap for depositing a substance, e.g. a lubricant, on the skin surface during shaving. For the most part these known blade units produce very satisfactory results. However, due to the presence of more than one blade and the particular guard and cap structure, the blade units generally contact the skin over a relatively large area and some shavers experience difficulties in shaving areas in tight corners where access by the razor is restricted by facial features such as under the nose and near the ears.
With a view to enabling the blade unit to follow the skin contours in the performance of a shaving stroke, it is well known to mount the blade unit for pivotal movement about an axis which extends parallel to the cutting edges of the blades. On the whole the pivotal movement of the blade unit relative to the handle facilitates the use of the razor by making the shaving efficiency less sensitive to small changes in handle orientation with respect to the skin as the blade unit performs a shaving stroke. It has been found that some shavers can experience difficulty, due to pivoting of the blade unit, in obtaining an optimum positioning of the blade unit against the skin when attempting to shave areas in tight corners. Also, there is a tendency for users of safety razors to wish to press the blade unit of a razor harder against the skin when trimming longer hairs, for example the sideburns, and the pivotal movement of the blade unit can sometimes be perceived to act to thwart such attempts to increase the force with which the blade cutting edges are urged against the skin.
In view of the foregoing considerations there is a need for a safety razor blade unit which is better able to satisfy the requirements of all consumers with respect to trimming longer hairs and shaving skin areas to which razor access is restricted.
There have been proposals to provide safety razors which provide increased versatility as to the manner in which they may be used for shaving. In U.S. Pat. No. 5,199,173 for example there is described a safety razor with an arched blade unit with blades providing cutting edges at both the concave and convex sides, the blade unit being selectively rotatable on the razor handle to bring the concave or convex side into an operative shaving position. GB-A-2179286 proposes a razor with two blade units pivotally mounted on a handle independently of each other and positioned on the handle to facilitate shaving the left and right sides of the face. U.S. Pat. No. 2,439,909 describes a safety razor that, rather than having blades with rectilinear cutting edges, has fixedly mounted on the razor handle a curved foil with slots that are inclined to the shaving direction in which the foil is moved across the skin during shaving and have sharpened cutting edges, there being in addition a further slot with a sharp cutting edge extending laterally across the foil behind the inclined slots, and this cutting edge associated with the additional slot being intended for hair trimming purposes. WO-A-91/01204 also describes a razor having a blade unit equipped foil blade provided with sharp-edged apertures for shaving, the blade unit being held stationary relative to the razor handle during normal shaving, but being pivotally adjustable to expose a sharp cutting edge at the leading edge of the foil for hair trimming purposes. None of the prior art proposals are suitable for adoption in the known multi-bladed safety razor blade units intended to perform pivotal movements during shaving, with a view to improving the ability of such blade units to shave areas to which access is restricted and/or to trim longer hairs.
There is described in U.S. Pat. No. 6,276,061 a safety razor blade unit having three blades with cutting edges disposed between guard and cap surfaces at a top face of the blade unit, and a further trimming blade is located at the rear face at an angle of 60-120°, particularly 85-95°, to the angle of the other three blades. The blade unit has no apparent skin contact surfaces associated with the trimming blade to control the engagement of this blade with the skin, and soap and shaving debris collecting under the trimming blade can not easily be rinsed away.